1. Field of the Invention
This invention relates to removing coupling elements of a synthetic resin to form element-free space resistors in a slide fastener chain including a pair of rows of interengaged discrete coupling elements mounted on confronting edges of a pair of fastener tapes.
2. Prior Art
One conventional method of forming element-free space sections in a slide fastener chain provided with synthetic resin coupling elements is disclosed, for example, in UP, U no. 55-109410 (Japanese unexamined utility Model Publication). This method for forming space sections free of coupling elements in a slide fastener chain includes the steps of: putting the slide fastener chain on a die provided with a through hole of the element width at the center position; actuating a punch provided with two steps on side faces thereof to descend from an upward position toward the coupling elements to punch the heads; and continuing the descent of the punch to catch and remove legs that remain in the fastener tape by the punch step.
However, the above-mentioned element-free space section forming method suffers from several drawbacks. For example, sine the punch descends to punch the heads of the coupling elements, and continues its descent to catch and remove the remaining cut legs by the punching process, the stringer cores of the fastener tape are susceptible to damage. Descent of the punch sometimes results in chain breakage. Furthermore, a large force is required in order to punch and remove legs in one operation.